1. Field of the Invention
The present invention relates generally to image capturing methods, and more particularly, to a method and apparatus for capturing a still image while continuously capturing a moving image.
2. Description of the Related Art
A digital image capturing apparatus can provide both moving-still capturing and still-image capturing. A dual recording function has also been provided in which a still image is generated at the request of a user while capturing a moving image. The moving-image capturing is automatically continued.
Generally, in dual recording, the digital image capturing apparatus records a still image that has the same pixels as those in moving-image capturing.
To acquire a still image having a resolution that is higher than a moving image, an image sensor of the digital image capturing apparatus continuously outputs image data having full pixels or high pixels during moving-image capturing. An Image Signal Processor (ISP) having received the image data from the image sensor processes the quality of the image data to suitably reduce pixels of the image data for the moving-image capturing pixels, and outputs a moving-image frame data. Once the user presses a still-image capturing button during moving-image capturing, the ISP processes the quality of the image data to the full pixels or high pixels, thus outputting still-image data having the full pixels or high pixels.
If a moving-image processor and a still-image processor are provided in the ISP, a moving image and a still image can be processed at the same time. The image sensor is driven with the full pixels or high pixels at all times, such that in still-image capturing during moving-image capturing, mode change of the image sensor is not required and the screen stop or time loss phenomenon does not occur.
In conventional dual recording in which a high-resolution still image is captured, the image sensor is driven with the full pixels or high pixels during moving-image capturing and thus outputs the image data. The ISP receives and processes the image data, such that power consumption is larger than common moving-image capturing, which drives the image sensor with partial pixels.
In particular, as the number of pixels of the image sensor increases and a moving-image capturing frame rate increases, the image sensor and the ISP are required to operate at high speeds, power consumption increases, and quality degradation becomes worse due to heat generation. For this reason, a full-pixel operating frame rate does not reach a moving-image capturing frame rate.
To solve this problem, the image sensor may be driven with a small pixel number and a still-image pixel number may be increased through scaling up. However, a resulting substantial resolution increase effect is not satisfactory.